From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f208.google.com (mail-oi1-f208.google.com [209.85.167.208]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0107939A06C for ; Sat, 1 Aug 2026 00:55:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.208 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785545739; cv=none; b=Cx/Bx0jkDV/vnEWJFHDs+9UI0hswY4ieSt9xS+/Xg2IDd6r3SRS2YwQOR9bz35fxPcJdm4eEMVG75EeQbQ6Rut3O9SaXkfUR9sxo02FnhiBQnO4rscHtnpm+kphtm7S8GSv5TkJdBLkXni1QYub19Wa9uYzXvUyZ9Wjsw4izRtg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785545739; c=relaxed/simple; bh=aWz4kcV/AjqntA6nJMXU3T9F1qlrOtVLGAyfwShjzng=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=HZGMDTIm9ucsumDM2kiCXhvdPMPp62Gph51vsu5jEnFBF//ZTiBrtaf4LYzsui5qd20TFchQ6PUtfswtEO/RbjNUQtRHNrHxEbZ8iFoUyHwO2fklIoWC0AzED3wopwE9Y0nD4pZTFaw1TGLTSNecdKTHmhYdC9FePmgqhKEZ5PY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.167.208 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f208.google.com with SMTP id 5614622812f47-4ab7bb257bbso1345180b6e.0 for ; Fri, 31 Jul 2026 17:55:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785545734; x=1786150534; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ZA5LvUEt2FwGgOBdTzltpKIALnlVONsI8sGo9/aAobg=; b=RtbLKRW++jkd7Du2O0dmAjEnCODBpk5JJs+wJ6W5JdxT0L6iWILA+H9uMPgiIAQKmy D0Ugs5+fWQwlWPicF7WkomlHlAWWSZxm8jenNGT5hlsdSm1YgrbnR9cXsdzHYCmmTDeR 9zGxYJ9F4lAB3ovsaJMLHt1P2tgGL4S9YQ0KS3x7+TeKUAyt1UO+TaPBx5xo/6IRyh9F thJypf+mlnzOq/IW21OhF03pcGrz+Wfvh5LikEF4ejRb3sEsyDy+oeLzqgL5MBjQndoi xnHKqeTotf0l8m/TuzFM/d3XPqZ2JG2SwxA5gaMuFvu2n89R3hXueJ5CZIYhSPs+6mlC kASg== X-Forwarded-Encrypted: i=1; AHgh+RqzFV7ojSMI0h6TP2lzD0/VmcpCHzOJsZ97bTcwFk+ZfH9AOROGV1GqXCVjEg/1/Fla6Pn5fk0=@vger.kernel.org X-Gm-Message-State: AOJu0YxR7lSm8fbIdYl8EaLf7GSW4x+YEuSYZz1MpfTzBuEycCZmzDEJ JilDkGw1UoDRizdKbbT5mrZVdB/Pn8qq2xZm53QPm3VKYqMsnTrDHhWTzwqllQA0a+eqT21x7X/ bZVnpiJj+BDgFwI3kgD7qfGOvRtBxNmIPBhmyh1iDT1CjO9FHCX5PJOs+Lvs= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:2225:b0:4ab:230c:5faa with SMTP id 5614622812f47-4af5e3e5522mr3607854b6e.18.1785545734163; Fri, 31 Jul 2026 17:55:34 -0700 (PDT) Date: Fri, 31 Jul 2026 17:55:34 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a6d4406.2d659fcc.1d46f5.01ad.GAE@google.com> Subject: [syzbot] [bridge?] KASAN: slab-use-after-free Read in br_handle_frame From: syzbot To: bridge@lists.linux.dev, davem@davemloft.net, edumazet@google.com, horms@kernel.org, idosch@nvidia.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, razor@blackwall.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 04026c998c24 net/rds: use krealloc_array() for iovector gr.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=1141c49e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f9f592a4e0cc86da dashboard link: https://syzkaller.appspot.com/bug?extid=128e9f5a0f85a51215b1 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4f82b6352d02/disk-04026c99.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9b29e52c71b2/vmlinux-04026c99.xz kernel image: https://storage.googleapis.com/syzbot-assets/0b1e84e828d6/bzImage-04026c99.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+128e9f5a0f85a51215b1@syzkaller.appspotmail.com bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ================================================================== BUG: KASAN: slab-use-after-free in is_multicast_ether_addr include/linux/etherdevice.h:133 [inline] BUG: KASAN: slab-use-after-free in is_valid_ether_addr include/linux/etherdevice.h:209 [inline] BUG: KASAN: slab-use-after-free in br_handle_frame+0xcfb/0x1510 net/bridge/br_input.c:349 Read of size 4 at addr ffff88807c476008 by task kworker/R-bat_e/3227 CPU: 1 UID: 0 PID: 3227 Comm: kworker/R-bat_e Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: bat_events batadv_tt_purge Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 is_multicast_ether_addr include/linux/etherdevice.h:133 [inline] is_valid_ether_addr include/linux/etherdevice.h:209 [inline] br_handle_frame+0xcfb/0x1510 net/bridge/br_input.c:349 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6102 __netif_receive_skb_one_core net/core/dev.c:6213 [inline] __netif_receive_skb net/core/dev.c:6328 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6679 __napi_poll+0xaa/0x330 net/core/dev.c:7738 napi_poll net/core/dev.c:7801 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7958 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x2c1/0x340 net/batman-adv/translation-table.c:1366 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3565 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 rescuer_thread+0x7b6/0x10b0 kernel/workqueue.c:3629 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5627: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5362 [inline] __kmalloc_node_track_caller_noprof+0x4c3/0x730 mm/slub.c:5497 kmalloc_reserve net/core/skbuff.c:637 [inline] __alloc_skb+0x2bd/0x7a0 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] mld_newpack+0x165/0xcb0 net/ipv6/mcast.c:1790 add_grhead net/ipv6/mcast.c:1901 [inline] add_grec+0x119f/0x19d0 net/ipv6/mcast.c:2040 mld_send_cr net/ipv6/mcast.c:2126 [inline] mld_ifc_work+0x30e/0xd60 net/ipv6/mcast.c:2711 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 3227: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kfree+0x1c5/0x640 mm/slub.c:6720 skb_kfree_head net/core/skbuff.c:1077 [inline] skb_free_head net/core/skbuff.c:1089 [inline] pskb_expand_head+0x469/0x13a0 net/core/skbuff.c:2338 netif_skb_check_for_xdp net/core/dev.c:5580 [inline] netif_receive_generic_xdp net/core/dev.c:5611 [inline] do_xdp_generic+0x9a5/0x12d0 net/core/dev.c:5679 __netif_receive_skb_core+0x10e0/0x30b0 net/core/dev.c:6025 __netif_receive_skb_one_core net/core/dev.c:6213 [inline] __netif_receive_skb net/core/dev.c:6328 [inline] netif_receive_skb_internal net/core/dev.c:6414 [inline] netif_receive_skb+0x1fe/0xbf0 net/core/dev.c:6473 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:325 br_handle_frame_finish+0x1192/0x1990 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6102 __netif_receive_skb_one_core net/core/dev.c:6213 [inline] __netif_receive_skb net/core/dev.c:6328 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6679 __napi_poll+0xaa/0x330 net/core/dev.c:7738 napi_poll net/core/dev.c:7801 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7958 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x2c1/0x340 net/batman-adv/translation-table.c:1366 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3565 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 rescuer_thread+0x7b6/0x10b0 kernel/workqueue.c:3629 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88807c476000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 8 bytes inside of freed 2048-byte region [ffff88807c476000, ffff88807c476800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807c472000 pfn:0x7c470 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801b005000 ffffea0001f06210 ffffea00013ad810 raw: ffff88807c472000 0000000800080001 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b005000 ffffea0001f06210 ffffea00013ad810 head: ffff88807c472000 0000000800080001 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 29164, tgid 29161 (syz.4.10629), ts 619315175671, free_ts 619310279727 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3294 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3408 new_slab mm/slub.c:3454 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7338 refill_sheaf mm/slub.c:2832 [inline] __pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4703 alloc_from_pcs mm/slub.c:4801 [inline] slab_alloc_node mm/slub.c:4933 [inline] __do_kmalloc_node mm/slub.c:5361 [inline] __kmalloc_node_track_caller_noprof+0x557/0x730 mm/slub.c:5497 kmalloc_reserve net/core/skbuff.c:637 [inline] __alloc_skb+0x2bd/0x7a0 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] alloc_skb_with_frags+0xc6/0x760 net/core/skbuff.c:6769 sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:3013 sock_alloc_send_skb include/net/sock.h:1907 [inline] llc_ui_sendmsg+0x459/0xe30 net/llc/af_llc.c:968 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] sock_sendmsg+0x1ca/0x2d0 net/socket.c:813 splice_to_socket+0xb5e/0x12a0 fs/splice.c:884 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1159 splice_direct_to_actor+0x57b/0xcb0 fs/splice.c:1103 page last free pid 29163 tgid 29158 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 rcu_do_batch kernel/rcu/tree.c:2645 [inline] rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897 handle_softirqs+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 Memory state around the buggy address: ffff88807c475f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807c475f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807c476000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807c476080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807c476100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup